LININ: Logic Integrated Neural Inference Network for Explanatory Visual Question Answering

Explanatory Visual Question Answering (EVQA) is a recently proposed multimodal reasoning task consisting of answering the visual question and generating multimodal explanations for the reasoning processes. Unlike traditional Visual Question Answering (VQA) task that only aims at predicting answers for visual questions, EVQA also aims to generate user-friendly explanations to improve the explainability and credibility of reasoning models. To date, existing methods for VQA and EVQA ignore the prompt in the question and enforce the model to predict the probabilities of all answers. Moreover, existing EVQA methods ignore the complex relationships among question words, visual regions, and explanation tokens. Therefore, in this work, we propose a Logic Integrated Neural Inference Network (LININ) to restrict the range of candidate answers based on first-order-logic (FOL) and capture cross-modal relationships to generate rational explanations. Firstly, we design a FOL-based question analysis program to fetch a small number of candidate answers. Secondly, we utilize a multimodal transformer encoder to extract visual and question features, and conduct the prediction on candidate answers. Finally, we design a multimodal explanation transformer to construct cross-modal relationships and generate rational explanations. Comprehensive experiments on benchmark datasets demonstrate the superiority of LININ compared with the state-of-the-art methods for EVQA.